The diversity and complex regulation of intercellular signaling protein (ISP) networks in the biochemical makeup of heterogeneous nervous tissues presents a formidable challenge in the investigation Of the cell-to-cell signaling roles in sophisticated behavioral phenomena such as addiction. To address this issue, a core facility dedicated to customizing sampling and separation methods to profile the ISPs in single cells, specific brain regions, and extracellular fluids will be established within the proposed UIUC center. These technologies wilt be applied to ISP profiles within the nervous system in the study of fundamental neuroscience as well as pathological conditions such as drug-of-abuse-induced changes. To profile ISP in specific brain tissues and cells this Core will specialize in: 1.) collecting and fractionating biological samples including simultaneous preparation of large numbers of rapidly acquired, nanoliter volume biological samples; 2.) applying directed sampling methodologies to single cells, spatially distinct brain regions, and biological fluids to collect ISPs; and 3.) optimizing preparation of fractionated samples and tissues for mass spectrometry including imaging MS approaches. Established techniques such as 2-D electrophoretic separations as well as state-of-the-art sampling, separation, and quantitative approaches will be used to prepare a large range of ISP-containing fractions ready for MS analysis at the Protein Identification Core. This overarching strategy provides the flexibility to individually tailor isolation and detection methodology for ISP profiles inherently unique to the neurobiological phenomena investigated by the center's biological user base.